If a = 5i - j - 3k and b = i - 3j - 5k then (a+b).(a-b) is equal to: Option 1: 1 Option 2: 0 Option 3: 48 Option 4: -48

The answer is '0'. View full solution:

CUET Mathematics - If a = 5i - j - 3k and b = i - 3j - 5k then (a+b).(a-b) is equal to: | PYQs + Solutions

CUET Mathematics 2026 26th May Shift 2

Algebra

Easy

core

-48

✅ Correct Option: 2

Related questions:

22nd May Shift 1

If $|\vec a|=2, |\vec b|=7$ and $\vec a\times\vec b=3\hat i+2\hat j+6\hat k$ , then angle between $\vec a$ and $\vec b$ is:

22 May Shift 3

Match List - I with List - II.

	List - I		List - II
(A)	Area of triangle $\Delta$ with adjacent sides $\vec{a}$ and $\vec{b}$	(I)	$\vec{a} \times \vec{b}$
(B)	Area of parallelogram with adjacent sides $\vec{a}$ and $\vec{b}$	(II)	$\frac{1}{2}\lvert \vec{a} \times \vec{b} \rvert$
(C)	$(\vec{a} - \vec{b}) \times (\vec{a} + \vec{b})$	(III)	$\lvert \vec{a} \times \vec{b} \rvert$
(D)	$\lvert \vec{a} \rvert \lvert \vec{b} \rvert \sin\theta \hat{n}$ , where symbols have their usual meaning	(IV)	$2(\vec{a} \times \vec{b})$

Choose the correct answer from the options given below :

22nd May Shift 1

If $\vec a$ and $\vec b$ are two unit vectors and $|\vec a-\vec b|=\sqrt3$ , then the value of $|\vec a+\vec b|$ is: